Hurricane Sandy hopefully will prove to be a turning point in American government and politics. In less than a week’s time, U.S. citizens have gotten a few critical reminders: Civil servants and military adjutants alike become urgently important assets in a natural disaster. Federal agencies charged with emergency duties need resources to do their jobs. Risk sharing at a national level makes it possible to do things federally that you can’t do efficiently otherwise. Good science is essential to good public policy. Real storms make mincemeat out of small-minded squabbles.
Until now, that popular term “the perfect storm” referred to an unnamed hurricane that formed off the New England coast on Oct. 28, 1991. Hurricane Sandy took that mantle for itself as it struck the U.S. Northeast corridor on Monday, Oct. 29.
Sandy originated in a tropical wave formed in the Caribbean Sea and was identified by the National Hurricane Center on Oct. 20, 2012. NHC gave it a “high” probability of turning into a tropical cyclone. NHC’s 10-day-out weather model scenarios revealed a storm path likely to place the system close to the Mid-Atlantic as a major hurricane. Most model runs lose useful accuracy beyond 5 days, so there was little basis for alarm. Systemic elements of the wave initially were too complex to consider all possible variables very far ahead. However, by Oct. 21 meteorologists did take note when their simulation work pointed to a hurricane hit on New Jersey 10 days ahead.
On Oct. 22, NHC classified the wave as Tropical Depression 18. At that point, forecasting efforts revealed a tropical storm likely to travel over Jamaica, Cuba and the Bahamas, and then on up into the Western Atlantic Ocean. At that point, factors including warm water temperatures, low wind shear, and high moisture levels all proved conducive for strengthening the depression to hurricane force. This came to fruition by time it reached Jamaica. Even at that point, forecast spreads remained ambiguous.
NHC meteorologists proved to be proactive in extending their analysis though. By this time they were running comparisons of alternate weather model outcomes using spaghetti model plots to get a gauge on where the cyclone center might go according to a large number of alternate weather forecasting models. Much of this analysis also showed Sandy hitting land somewhere between Maryland and Connecticut in the week ahead.
By Oct. 23 the National Weather Service ordered a doubling of weather balloon releases from two to four times daily in order to get more data – and to reduce variability in forecast results. This step was a repeat of what the agency did successfully in 2011 during the build-up of Hurricane Irene. The forecasting results were amazingly accurate. By evening on Oct. 25, NHC’s five-day forecast put Sandy’s likely landfall very close to where the storm actually hit, just a few miles south of Atlantic City, N.J.
A complex set of circumstances made this forecasting work unusually challenging. Several different meteorological circumstances played into the strange left hook that swung Sandy off from its Atlantic Ocean course toward land. There was an Arctic air mass moving in, which drew the cyclone in. A high pressure area north of New England blocked Sandy from riding the coast northward and forced it inland. Northeast of Sandy was a low pressure center which kept it from following a course out to sea. These factors combined to send Sandy northwest, heading into the most populated region of the U.S.
Meteorologists knew that the risk potential heightened greatly once Sandy sustained its strengthening over Jamaica. When the storm sustained deep enough pressure moving over mountainous areas in Cuba, it got a big lead to strengthen once it reached the Gulf Stream. It weakened a bit from wind shear and dry air moving through the Bahamas, but it was already strong enough by then to manifest further dropping in air pressure.
By Oct. 25, temperature readings revealed enough detail about the Arctic air movement ahead to figure in possible interactions with Sandy.
This is where the concept of air pressure and something called “baroclinic forcing” comes into play. Cold Arctic air in collision with warm tropical air suddenly appeared likely to cause baroclinic forcing, which would allow Sandy’s pressure to deepen even further. Instead of turning air pressure into stronger winds, Sandy turned its energy into expansion of its wind field – a full 520 mile diameter from center to winds’ edge. This contributed greatly to the vast water bubble effect that flooded coastal areas far beyond anything experienced in U.S. history.
Extratropical transition is the technical name of what happened. This process happens when a tropical cyclone takes in colder air, which turns the center of the system into a cold-core. This results in the formation of warm and cold fronts that can make a storm massive. Combine that with deep air pressure gradients, and you have a recipe for sustained wind damage as well as unusually high measures of storm surge. Sandy’s storm surge was exacerbated by the fact that the storm hit land at high tide. The coincidence of a full moon at that time strengthened the surge even further. On top of that, Sandy’s extremely low air pressure added a foot of water in some places.
Blizzard conditions figured into the storm impact to make Sandy’s consequent misery levels even worse. Weather conditions from this deadly mix of weather fronts reached all the way from the coastline in as far westward as Ohio. High ridges in West Virginia experienced as much as 50 inches of snow.
Because our government’s weather professionals went the extra mile in anticipating a looming emergency, it was possible for emergency management agencies to preposition assets in advance of a disastrous weather event which could have been far worse otherwise. Electoral implications of the storm are trivially transient considerations. The storm does speak to us meaningfully though when it comes to good government.
It’s worth giving real heed now to recent remarks by New York City Mayor Michael Bloomberg and commentary by Bloomberg Businessweek : “It’s Global Warming, Stupid!”
When it comes to protecting public safety and furthering the public interest, the name of the game here is science. It takes jacks or better to be in the game – and there’s no place for jokers in the deck.